Ch 16 Mastering

What is the role of DNA polymerase during DNA synthesis? DNA polymerase removes inorganic phosphate from the template strand of DNA to catalyze the polymerization reaction. DNA polymerase is the enzyme that catalyzes the addition of a nucleotide onto the 3' end of a growing DNA strand. DNA polymerase provides the free energy to catalyze the endergonic addition of a nucleotide onto the 3' end of a growing DNA strand. DNA polymerase catalyzes the synthesis of the template strand of DNA.

A hydroxyl is present at the 3' end of the growing DNA strand. What is at the 5' end? a nitrogenous base a phosphate group a deoxyribose a ribose

Addition of a nucleotide onto a DNA strand is an endergonic reaction. What provides the energy to drive the reaction? Release of pyrophosphate from the incoming nucleotide, and then hydrolysis of the pyrophosphate to inorganic phosphate The dehydration reaction between the 5'-phosphate of the incoming nucleotide and the 3'-OH of the growing strand of DNA Complementary bases on the template and the incoming nucleotide are attracted to each other, releasing free energy. Binding of the pre-existing new strand, the template strand, and the incoming nucleotide to the active site of the DNA polymerase

Given a template strand of 3'-ATGCTTGGACA-5' and a partially-made complementary strand containing only 5'-TAC-3', what would be the sequence of the new strand of DNA (including the 5'-TAC-3') if the only additional nucleotides available to DNA polymerase were those containing the bases G, A, and C? 3'-TACGAACCTGT-5' 5'-GAACC-3' 5'-TAC-3'; All four nucleotides are required for DNA polymerase to function. 5'-TACGAACC-3'

The new DNA strand that grows continuously in the 5' to 3' direction is called the___________

After replication is complete, the new DNAs, called__________are identical to each other.

___________are the short sections of DNA that are synthesized on the lagging strand of the replicating DNA.

The enzyme that can replicate DNA is called_________

During DNA replication, an open section of DNA, in which a DNA polymerase can replicate DNA, is called a___________

The two strands of a DNA double helix are held together by _____ that form between pairs of nitrogenous bases. disulfide (S−S) bonds covalent bonds hydrogen bonds ionic bonds

Which of these is a difference between a DNA and an RNA molecule? DNA is a polymer composed of nucleotides, whereas RNA is a polymer composed of nucleic acids. DNA is usually double-stranded, whereas RNA is usually single-stranded. DNA contains nitrogenous bases, whereas RNA contains phosphate groups. DNA contains five-carbon sugars, whereas RNA contains six-carbon sugars. DNA contains uracil, whereas RNA contains thymine.

Which of these nitrogenous bases is found in DNA but not in RNA? adenine thymine uracil guanine cytosine

n a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand. guanine ... adenine = cytosine ... thymine cytosine ... uracil uracil ... cytosine

It became apparent to Watson and Crick after completion of their model that the DNA molecule could carry a vast amount of hereditary information. Which of the following characteristics of DNA is responsible for this? phosphate-sugar backbones side groups of nitrogenous bases sequence of bases complementary pairing of bases

In the polymerization of DNA, a phosphodiester bond is formed between a phosphate group of the nucleotide being added and which of the following atoms or molecules of the last nucleotide in the polymer? a nitrogen from the nitrogen-containing base the 5' phosphate the 3' OH C6

In a DNA double helix an adenine of one strand always pairs with a(n) _____ of the complementary strand, and a guanine of one strand always pairs with a(n) _____ of the complementary strand cytosine ... thymine guanine ... adenine uracil ... cytosine thymine ... cytosine cytosine ... uracil

After DNA replication is completed, _____. each of the four DNA strands consists of some old strand parts and some new strand parts one DNA double helix consists of two old strands and one DNA double helix consists of two new strands each new DNA double helix consists of one old DNA strand and one new DNA strand each new DNA double helix consists of two new strandsthere are four double helices

The first step in the replication of DNA is catalyzed by _____ single-strand binding protein primase ligase DNA polymerase helicase

The action of helicase creates _____ primers and DNA fragments DNA fragments and replication bubbles replication forks and replication bubbles primers and replication bubbles DNA fragments and replication forks

Why is the new DNA strand complementary to the 3' to 5' strands assembled in short segments? DNA polymerase can assemble DNA only in the 5' to 3' direction DNA polymerase can assemble DNA only in the 3' to 5' direction only short DNA sequences can extend off the RNA primers the replication forks block the formation of longer strands it is more efficient than assembling complete new strands

Short segments of newly synthesized DNA are joined into a continuous strand by _____. single-strand binding protein DNA polymerase primase ligase helicase

After DNA replication is completed, _____. one DNA double helix consists of two old strands and one DNA double helix consists of two new strands each new DNA double helix consists of two new strands there are four double helices each new DNA double helix consists of one old DNA strand and one new DNA strand each of the four DNA strands consists of some old strand parts and some new strand parts

What catalyzes DNA synthesis? DNA polymerase Primer Replication forkd NTPs

Which part of a deoxynucleoside triphosphate (dNTP) molecule provides the energy for DNA synthesis? Base Free 3' hydroxyl (-OH) group Sugar Phosphate groups

Which of the following enzymes creates a primer for DNA polymerase? Ligase Helicase Primase Topoisomerase

Which of the following enzymes is important for relieving the tension in a helix as it unwinds during DNA synthesis? Single-strand binding proteins Ligase Helicase Topoisomerase

What is meant by the description "antiparallel" regarding the two strands that make up the DNA double helix? Base pairings create unequal spacing between the two DNA strands. One strand contains only purines and the other contains only pyrimidines. The 5' to 3' direction of one strand runs counter to the 5' to 3' direction of the other strand. The double helix structure of DNA creates nonparallel strands.

In E. coli, which enzyme catalyzes the elongation of a new DNA strand in the 5' → 3' direction? DNA polymerase III helicase DNA ligase primase

At a specific area of a chromosome, the sequence of nucleotides below is present where the chain opens to form a replication fork:3' C C T A G G C T G C A A T C C 5'An RNA primer is formed starting at the underlined T (T) of the template. Which of the following represents the primer sequence? 5' A C G U U A G G 3' 5' G C C T A G G 3' 5' A C G T T A G G 3' 5' G C C U A G G 3'

Which of the following statements correctly describes the difference between the leading and the lagging strands of DNA during DNA replication? The leading strand is synthesized by adding nucleotides to the 3' end of the growing strand, and the lagging strand is synthesized by adding nucleotides to the 5' end. The leading strand is synthesized in the same direction as the movement of the replication fork, and the lagging strand is synthesized in the opposite direction. The lagging strand is synthesized continuously, whereas the leading strand is synthesized in short fragments that are ultimately stitched together. The leading strand is synthesized at twice the rate of the lagging strand.

Why does a new DNA strand elongate only in the 5' to 3' direction during DNA replication? Replication must progress toward the replication fork. DNA polymerase can add nucleotides only to the free 3' end. The polarity of the DNA molecule prevents addition of nucleotides at the 3' end. DNA polymerase begins adding nucleotides at the 5' end of the template.

What is the function of the enzyme topoisomerase in DNA replication? relieving strain in the DNA ahead of the replication fork caused by the untwisting of the double helix elongating new DNA at a replication fork by adding nucleotides to the existing chain building RNA primers using the parental DNA strand as a template reattaching the hydrogen bonds between the base pairs in the double helix

What is the role of DNA ligase in the elongation of the lagging strand during DNA replication? It synthesizes RNA nucleotides to make a primer. It joins Okazaki fragments together. It unwinds the parental double helix. It stabilizes the unwound parental DNA

Which of the following types of molecules help to hold the DNA strands apart while they are being replicated? primase single-strand DNA binding proteins ligase DNA polymerase

Within a double-stranded DNA molecule, adenine forms hydrogen bonds with thymine, and cytosine forms hydrogen bonds with guanine. What is the significance of the structural arrangement? It determines the tertiary structure of a DNA molecule. It allows variable width of the double helix. It permits complementary base pairing. It determines the type of protein produced.

Semiconservative replication involves a template. What is the template? one strand of the DNA molecule an RNA molecule single-stranded binding proteins DNA polymerase

Which of the following statements correctly describes the difference between the leading strand and the lagging strand in DNA replication? The leading strand requires an RNA primer, whereas the lagging strand does not. There are different DNA polymerases involved in elongation of the leading strand and the lagging strand. The leading strand is synthesized continuously in the 5' → 3' direction, while the lagging strand is synthesized discontinuously in the 5' → 3' direction. The leading strand is synthesized in the 3' → 5' direction in a discontinuous fashion, while the lagging strand is synthesized in the 5' → 3' direction in a continuous fashion.

What are chromosomes made of? DNA, heterochromatin, and histone proteins DNA, RNA, and proteins DNA DNA and euchromatin DNA and proteins

Which of the following is true of DNA during interphase? It is in the form of highly condensed chromosomes; it is called heterochromatin. It exists as chromatin and is unavailable for gene expression. It exists as chromatin and is less condensed than mitotic chromosomes. It exists as chromatin; it is completely uncoiled and loose.It is in the form of highly condensed chromosomes and is unavailable for gene expression.

Which of the following statements accurately describes the structure of a eukaryotic chromosome? It has different numbers of genes in different cell types of an organism. It is composed of a single strand of DNA. It is constructed as a series of nucleosomes wrapped around two DNA molecules. It is a single linear molecule of double-stranded DNA plus proteins.

DNA is a self-replicating molecule. What accounts for this important property of DNA? Replication is thermodynamically spontaneous and requires no enzymes. Its two strands are held together by easily broken covalent bonds. The nitrogenous bases of the double helix are paired in specific combinations: A with T and G with C.

During DNA replication, the leading strand is synthesized continuously, whereas the lagging strand is synthesized as Okazaki fragments. Why is this so? DNA synthesis can take place only in the 5' to 3' direction. DNA polymerases can bind to only one strand at a time. There are thousands of origins of replication on the lagging strand but only one on the leading strand.